Dynamic characteristics of misaligned gear coupling-bearing-rotor system

For meeting the requirement of the simulated operation of a high-speed turbopump in liquid rocket engine，an internal gear coupling was designed as the key component to transfer the motion during the fast start-up stage.The misalignment of the center axis between the turbo rotor and the test rotor had a significant impact on the dynamics performance of the test rotor.The stiffness and damping theoretical model of the internal gear coupling，the model for solving additional forces and moments of the gear coupling under various misalignment conditions，and the dynamic model considering the misalignment factor for double rotor system coupling the gear coupling and the rolling bearing were proposed.The influences of the misalignment parameters on the dynamic performance (critical speed and vibration response) of the test rotor were obtained by numerical solution of the above coupled models，and the model verification was completed by comparing with the literature.The results showed the vibration response error between the proposed model and literature was less than 15%，and shortening the gear coupling length and increasing the center axis alignment can reduce effectively the dynamic response of the rotor system，and had little effect on the critical speed of the double rotor system.The research results provide a theoretical and experimental reference for the design and safe operation of high-speed turbopump.